Basic oxygen furnace construction



Dec. 19, 1967 O -N. T. CRICHTON 3,358,987

BASIC OXYGEN FURNACE CONSTRUCTION Filed Aug. 17, 1965 2 Sheets-Sheet 1 //VVEW70/ NEIL 'l'. CRICHTON Dec. 19, 1967 N. T. CRICHTON 3,358,987

BASIC OXYGEN FURNACE CONSTRUCTION Filed Aug. 17, 1965 2 Sheets-Sheet 2 INVENTOR NEIL T CRICH'TON 117' TORNEV United States Patent ABSTRACT OF THE DISCLOSURE A pair of shapes, one being seven-sided and the other of skew end shape; each of the pair having one arcuate surface; these arcuate surfaces together cooperating to form a common curve; the common curve seated to fill the knuckle area of an oxygen converter vessel.

In the oxygen steelmaking process, which has been variously designated as the LD process, oxygen Bessemer process and the oxygen converter process, the furnace structure fundamentally consists of a metal shell having a refractory lining disposed therein. The lining for oxygen steel furnaces consists of an inner or Working lining, and an exterior or tank lining, sometimes with an intermediate brick or rammed lining. The vessel is generally composed of three major zones, these three zones being the bottom zone, the barrel zone and the cone section zone. The bottom zone is generally dish-shaped and of upwardly opening concave configuration. The barrel zone extends from the dish-shaped bottom, upwardly to the cone section zone. The cone section zone is of downwardly opening, turncated cross section configuration. Brick used are usually key or wedge shaped. Usually, the brick in all three zones of the working lining are laid so that the end surface of smallest area is exposed to the interior of said vessel. Similarly, the brick in the tank lining are laid so that an end surface (usually the larger end) is adjacent the metal shell.

The area in the vessel where the barrel zone brick meet the bottom zone brick is referred as the knuckle area. At this point of meeting, the top and bottom face surfaces of the brick in the bottom zone are inclined from the vertical axis of the vessel; whereas, the top and bottom face surfaces of the brick in the barrel zone are substantially horizontal. Thus, in this area, the interior end surfaces of the brick in the barrel zone are closely adjacent the brick in the bottom zone while the opposite end surfaces thereof are widely separated.

The knuckle area between the brick in the bottom and barrel zones has become a major point of weakness of the structural integrity of the vessel. Various types of refractory shapes have been proposed to fill the void between these divergent brick in the shell protective lining or tank lining to provide resistance to stresses and strains encountered in vessel operation. These stresses and strains are caused by the physical movement and manipulation of the vessel or furnace itself during the steelmaking operation, i.e. wide and cyclic variation in temperature, due to successive charging and tapping of heats of metal from the vessel etc.

Accordingly, it is among the objects of the present invention to provide an improved knuckle area construction at the tank lining for oxygen steelmaking vessels.

Other objects of the invention will become apparent hereinafter.

In order to more fully understand the nature and scope of the invention, reference should be had to the following detailed description and drawings in which:

FIG. 1 is a schematic elevation view, partly broken, of a typical oxygen converter vessel;

FIG. 2 is a partial section of knuckle area construc- 3,358,987 Patented Dec. 19, 1967 tion in an oxygen converter vessel ent invention; and,

FIGS. 3 and 4 are perspective views of the refractory shapes employed in the knuckle area construction of FIG. 2.

Briefly, in accordance with the present invention, the improved construction in the knuckle area of a basic oxygen furnace shell protective lining consists of two contiguous courses of refractory brick. One course consists of seven-sided generally key type brick, one of which sides is arcuate. The other course consists of single end skew key brick, also having an arcuate side. Pairs of brick in each course are disposed so that the arcuate sides are adjacent the curvature in the shell and are in conformity therewith. The skew ends of the single end skew brick are contiguous with a side of the seven-sided brick in each course.

Referring to FIG. 1, there is shown a typical basic oxygen furnace 10 consisting of an outer metal shell 12, a shell protective brick lining 14 in contact with the inside surface of the shell and a brick Working lining 16. The vessel is constructed of three major zones, the bottom zone 18, the barrel zone 20, and the cone section Zone 22. The bottom zone is dish-shaped and of upwardly opening concave configuration. The brick 23, in the bottom zone, terminate in a knuckle area 24 with their face surfaces inclined from the vertical axis of the vessel. The barrel zone extends from the knuckle area upwardly to the cone section zone. The cone section zone, having a taphole' 26, extends upwardly and terminates in the form of a mouth 28 at the top of the vessel. The cone section zone is of downwardly opening, generally truncated conical cross section configuration. The brick 23 and 29 in the tank lining are contoured toward the knuckle 24 until the interior ends almost meet, thus leaving a void between the divergent face surfaces. The typical construction of FIG. 1 shows the knuckle area 24 to contain key type refractory brick in the shell protective lining 14 conforming to the contours of the shell. Such disposition of key brick in face surface to face surface abutment with each other and with the face surfaces of the terminal brick in the barrel and bottom zones was according to the presthought to provide a structurally sound knuckle area stresses and ultimate failure of the knuckle area construction at the tank lining and also subsequent failure in this area at the working lining, which resulted in considerable down-time and expense.

Referring to FIG. 2, there is shown a knuckle area construction according to the present invention. The improved construction employs brick of completely different design in the two courses utilized. The first brick shape 38 (shown best in FIG. 3) is a brick having key taper and having congruent face surfaces 40 and 42 and five incongruent side surfaces 44, 46, 48, 49 and 50. One of the side surfaces 50 is arcuate. The second refractory shape 51 is also a key tapered brick having congruent face surfaces 52 and 54, a skew end surface 56, and opposing end surface 58 and an arcuate side surface 60. Generally, a key brick is defined as one having six plane surfaces (two sides, two faces and two ends), in which two surfaces (the faces) are inclined toward each other and one of the end surfaces is narrower than the other. The seven-sided brick of this invention do not conform to this definition; however, for purposes of simplicity and explanation, we employ the term key taper to mean that the face surfaces of the brick are inclined toward each other.

The brick of FIGS. 3 and 4 are disposed in pairs so that the arcuate side surfaces 50 and 60 are in close relation to the curvature of the shell and are in conformity with the contours thereof. The brick 38 is further disposed so that the side surface 49 is contiguous with the skew end surface 58 of the brick 51. Another of the side surfaces 48, is contiguous withan inclined face surface 62 of the terminal brick in the inner course tank lining of the bottom zone. Another of the side surface 44, is contiguous with a face surface 64 of terminal brick in the barrel zone. The opposing end surface 58 of the brick 51, is contiguous with an inclined face surface 66 of the terminal, brick in the outer course tank lining of the bottom zone, and the opposing side surface 55 is contiguous with a plurality of end surfaces 68 of brick in the inner course tank lining of the bottom zone.

The above construction provides thrust support for both the shell and the barrel brick courses, and provides greater stability of the bottom zone brick courses. Further, the knuckle area brick, owing to their disposition, are placed in compression. Accordingly, the brick are not readily subject to shear stresses, as previously employed key brick,

and as a result, will better survive an extended number of furnace heats.

It is intended that the foregoing description and drawings be construed as illustrative and not in limitation of the invention.

Having thus described the invention in detail and with sufficient particularity as to enable those skilled in the art to practice it, what is desired to have protected by Letters Patent is set forth in the following claims:

I claim:

1. In an oxygen converter vessel comprising a metal shell having a mouth at its top, a shell protective lining in contact with the inside surface thereof and a working lining, said vessel being composed of three major zones, the bottom zone, the barrel zone and the cone section zone, the bottom zone being generally dish-shaped and of upwardly opening concave configuration, the brick in said zone terminating in a knuckle area, said knuckle area being characterized by a curvature in the shell bridging the bottom and barrel zones, the barrel zone extending from the knuckle area upwardly to the cone section zone, the cone section zone being of downwardly opening truncated cross section configuration, the improvement comprising a shell protective lining kunckle area construction consisting of, seven-sided brick, one of the sides being arcuate in vertical cross-section, and single end skew brick having a side which is arcuate in vertical cross-section, said sevensided and skew brick being disposed so that the arcuate sides thereof are in alignment to form a common curve and are adjacent the curavture in the shell in conformity therewith, the end skew of said latter brick being contiguous with a side of said seven-sided brick which intersects the arcuate side thereof.

2. In an oxygen converter vessel comprising a metal shell having a mouth at its top, a shell protective lining in contact with the inside surface thereof and a working lining, said vessel being composed of three major zones, the bottom zone, the barrel zone and the cone section zone, the bottom zone being generally dish-shaped and of upwardly opening concave configuration, the brick in said zone terminating in a knuckle area, said knuckle area being characterized by a curvature in the shell bridging the bottom and barrel zones, the barrel zone extending from the knuckle area upwardly to the cone section zone, the cone section zone being of downwardly opening truncated cross section configuration, the improvement comprising a shell protective lining knuckle area construction consisting of, first brick characterized by having congruent face surfaces and a plurality of incongruent side surfaces, one of the side surfaces being arcuate in vertical cross-section and second brick having a skew end surface and a surface which is arcuate in vertical cross section, said first and second brick being disposed so that the arcuate side surfaces thereof are in alignment to form a common curve and are adjacent the curvature in the shell in conformity therewith, the skew end surface of,

said latter brick being contiguous with a side surface of said first brick which intersects the arcuate side thereof.

3. In an oxygen converter vessel comprising a metal shell having a mouth at its top, a shell protective lining in contact with the inside surface thereof and a working lining, said vessel being composed of three major zones, the bottom zone, the barrel zone and the cone section zone, the three zones containing refractory brick having generally face, side and end surfaces, the bottom zone being generally dish-shaped and of upwardly opening concave configuration, the brick in said zone terminating in a knuckle area with their face surfaces inclined from the vertical axis of the vessel, said knuckle area being characterized by a curvature in the shell bridging the bottom and barrel zones, the barrel zone extending from the knuckle area upwardly to the cone section zone, the face surfaces of the brick in said zone being substantially normal to the vertical axis of the vessel, the cone section zone being of downwardly opening truncated cross section configuration, the improvement comprising a shell protective lining knuckle area construction consisting of seven-sided brick, one of the sides being arcuate in vertical cross-section and single end skew brick having an opposing end and a side which is arcuate in vertical crosssection, said seven-sided and skew brick being disposed so that the arcuate sides thereof are in alignment to form a common curve and are adjacent the curvature in the shell in conformity therewith, the skew end of said latter brick being contiguous with the side of said seven-sided brick which intersects the arcuate side thereof, another side of said seven-sided brick being contiguous with a face surface of the brick in the barrel zone, and the opposing end of said end skew brick being contiguous with a face surface of the inclined brick in the bottom zone.

4. In an oxygen converter vessel comprising a metal shell having a mouth at its top, a shell protective lining in contact with the inside surface thereof and a working lining, said vessel being composed of three, major zones, the bottom zone, the barrel zone and the cone section zone, the three zones containing refractory brick having generally face, side and end surfaces, the bottom zone being generally dish-shaped and of upwardly opening concave configuration, the brick in said zone terminating in a knuckle area, with their face surfaces inclined from the vertical axis of the vessel, said knuckle area being characterized by a curvature in the shell bridging the bottom and barrel zone, the barrel zone extending from the knuckle area upwardly to the cone section zone, the face surfaces of the brick in said zone being substantially normal to the vertical axis of the vessel, the cone section zone being of downwardly opening truncated cross section configuration, the improvement comprising a shell protec* tive lining knuckle area construction consisting of first brick having a key taper, characterized by having congruent face surfaces and a plurality of incongruent side surfaces, one of the side surfaces being arcuate and second brick having a key taper and having a skew end surface, an opposing end surface, opposing face surfaces and an arcuate side surface, said first and second brick being disposed so that the arcuate side surfaces are adjacent the curvature in the shell and are in conformity therewith, said first brick being further disposed so that one of said side surfaces is contiguous the skew end surface of said second brick, another of said side surfaces is contiguous with an inclined face surface of brick in the bottom zone and another of said side surfaces is contiguous with a face surface of brick in the barrel zone, said opposing end surface of the scond brick being contiguous with an inclined face surface of brick in the bottom zone.

5. At least a pair of refractory shapes suitable for use as a portion of a refractory lining in a basic oxygen vessel adjacent the are at its bottom, one of said pair of shapes being seven-sided, at least one of the sides being arcuate in vertical cross-section, the other of said pair being a single skew end shape also having an arcuate side in vertical cross-section, said pair being disposed so that the arcuate sides are in alignment to form a common curve and the skew end of the latter shape is contiguous with a side of said seven-sided shape which intersects the arcuate side thereof.

6. A refractory construction, suitable for use in the knuckle area of an oxygen converter vessel, having a refractory Working lining and tank lining, said knuckle area being characterized as the arcuate area in the vessel where the horizontal faced brick in the barrel zone adjacent the metal shell converge toward the inclined faced brick in the bottom zone adjacent the shell at the curvature in the metal shell and in which at least one interior course of inclined faced brick extends closer to the horizontal brick than exterior courses adjacent the shell, said construction being composed of preformed refractory having an arcuate surface conforming to the curvature in the metal shell, an upper surface forming a common corner with the arcuate surface for contiguous mating with the horizontal faced brick in the barrel zone, a lower side surface for contiguous mating With the interior extending inclined faced brick in the bottom zone, a lower side surface for contiguous mating with the exterior inclined faced brick in the bottom zone, a side surface for supporting a portion of the interior extending brick and a side surface for supporting a portion of the working lining.

References Cited UNITED STATES PATENTS OTHER REFERENCES Blast Furnace and Steel Plant, May 1959, p. 473.

Iron and Steel Engineer, vol. 43, No. 2, February 1966, p. 129.

The Refractories Journal, May 1964, p. 197.

J. SPENCER OVERHOLSER, Primary Examiner. E. MAR, Assistant Examiner. 

5. AT LEAST A PAIR OF REFRACTORY SHAPES SUITABLE FOR USE AS A PORTION OF A REFRACTORY LINING IN A BASIC OXYGEN VESSEL ADJCENT THE ARC AT ITS BOTTOM, ONE OF SAID PAIR OF SHAPES BEING SEVEN-SIDED, AT LEAST ONE OF THE SIDES BEING ARCUATE IN VERTICAL CROSS-SECTION, THE OTHER OF SAID PAIR BEING A SINGLE SKEW END SAPED ALSO HAVING AN ARCUATE SIDE IN VERTICAL CROSS-SECTION, SAID PAIR BEING DISPOSED SO THAT THE ARCUATE SIDES ARE IN ALIGNMENT TO FORM A COMMON CURVE AND THE SKEW END OF THE LATTER SHAPE IS CONTIGUOUS WITH A SIDE OF SAID SEVEN-SIDED SHAPE WHICH INTERSECTS THE ARCUATE SIDE THEREOF. 